What does the cryptic crossword clue "Ingredient of salad that's cold in the main (7)" mean?

The definition is "Ingredient of salad / that’s cold in the main". The wordplay uses a double definition. Double definition The answer is ICEBERG.

Ingredient of salad that's cold in the main (7)

Times Cryptic #29258 | 16 Across | 2025-06-17 flower